1. Field of the Invention
The invention relates to a vehicle transmission control console whereby shifting the transmission out of neutral is prevented when the parking brake is set, and whereby setting the parking brake is prevented when the transmission is in other than the neutral position.
2. Prior Art
A number of vehicle transmission control consoles are known which include means for preventing the operating transmission from somehow damaging itself. For example, U.S. Pat. No. 2,989,876 discloses a gear shift mechanism with an interlock which prevents shifting from the higher speed ratios of the transmission into reverse without preliminary engagement of the neutral position.
U.S. Pat. No. 3,480,120 relates to an apparatus for interlocking the transmission and parking brake controls. In this apparatus, interlocking parts between the parking brake and the transmission co-act to shift the transmission control linkage to a neutral position if the parking brake is applied when the transmission is not in neutral.
U.S. Pat. No. 3,566,711 is concerned with a gate plate for a transmission control box which serves in combination with certain slidable lock plates disclosed therein to allow actuation of a subordinate control only when a master control has been set in a particular position which is proper for the state of desired operation of the subordinate control. Also, the subordinate control can, at times, prohibit movement of the master control. The subordinate control may be, for example, a power take-off unit of one sort or another.
U.S. Pat. No. 3,597,991 is concerned with a selector mechanism which provides an automatic cancellation of one mode of operation when a second mode of operation is selected. More particularly, the apparatus disclosed includes two selecta levers which are interconnected by a linkage which includes cam surfaces. The cam surfaces are so constructed that when a forward drive ratio is selected a previously selected park or reverse position is automatically cancelled.
U.S. Pat. No. 3,601,231 relates to a parking brake and to a gear shift selector and parking brake lever controlling the positive locking of a drive shaft by a locking mechanism. The positive lock on the drive shaft prevents the rotation of the drive shaft and prevents the rear wheels of the vehicle from rotating.
U.S. Pat. No. 3,691,867 relates to a safety lever for the power shift transmission of a tractor in which the safety lever is movable to a transmission-unlocking position wherein the safety lever intervenes adjacent the tractor operator's seat to block the exit of the operator from the tractor, and in which the safety lever can be moved to a locking position wherein it no longer intervenes but at the same time either retains the transmission locked in neutral position or forces the transmission to take a neutralized setting and thereby cause the transmission to be retained in that setting.
U.S. Pat. No. 3,692,156 is concerned with a vehicle parking brake release control mechanism which is hydraulically actuated to release the parking brake. Transmission line pressure actuates the mechanism. The apparatus allows the application of the brake through the parking brake control mechanism to stop the vehicle.
U.S. Pat. No. 3,805,640 relates to electronic control means for operating a gear shift mechanism. The mechanism includes a lock-up clutch, operation of the controlling valve of which can be inhibited by the operation of a lock-up clutch solonoid valve.
It is clearly undesirable to drive a motor vehicle when the parking brake is set since this puts an extra strain on the vehicle motor and at the same time wears out the parking brake. To prevent accidental powered movement of a vehicle with the parking brake on, it is highly desirable to insure that the brake cannot be set in position unless the vehicle is first shifted into a neutral position. This prevents accidental actuation of the parking brake mechanism while the vehicle is moving. Further, it is most desirable that a vehicle be provided with a device to prevent an operator from shifting from a neutral position into a drive position when first starting up the vehicle and then driving the vehicle while the parking brake, which has been previously set in an on position, when the vehicle was parked, still remains on. It is further desirable to provide the above set out capabilities in a simple, direct and positive acting mechanism which is easily adjustable and repairable.
Accordingly, it is an object of the present invention to provide a positive acting interlock system for the parking brake and the gear shift regulator of a vehicle wherein the actuator which controls the parking brake also sets into motion means responsive to the movement thereof, which means causes interlocking of the actuator to the regulator only when the regulator is in the neutral setting whereby shifting out of neutral setting is prevented when the actuator and the regulator are interlocked and engagement of the brake is prevented when the regulator is not in the neutral setting.